1. Field of the Invention
This invention relates to materials for the manufacture of hollow jewellery from precious metal as gold or silver, and to methods of making such materials.
2. Description of the Prior Art
At present, hollow pieces of jewellery with a purity of 18 carats (750 mil.) can be obtained by plating brass sheet with gold leaf, drawing strands cut from a composite sheet thus plated on a brass core, forming pieces of jewellery from the strands obtained, and eliminating the brass with nitric acid.
It has been found that a process of this kind cannot be used for manufacturing pieces of hollow jewellery of low purity, for example 9 carats, because the nitric acid attacks such alloys.
Attempts have been made to use temporary substrates made of metals which undergo little or no oxidation under the plating conditions, such as aluminium. Unfortunately, the results obtained have not been satisfactory.